Superstar Ronaldo has told Real Madrid president Florentino Perez he is unhappy at the club and wants to leave in a shock move which has stunned the Spanish giants.

Now, City are working on an eye-watering four year contract offer to bring the former Manchester United star back to the Premier League.

Buying Ronaldo would mean boss Roberto Mancini having to sell players to clear space on City’s wage bill for the 27-year-old, who is paid around £250,000 a week in Madrid.

So it is unlikely to happen until next summer, when they feel Real could be forced to cash in on one of world football’s top talents for much less than his rumoured 1bn euro buy-out clause.

They feel the chance to sign a player of his class is too good to refuse – and hope to make some of it back in shirt sales and commercial tie-ups.

Ronaldo is about to take a massive hit on his salary when new laws come into force in Spain raising income tax by seven per cent to a whopping 52 per cent for high earners.

He has been trying to renegotiate his contract – which has three years to run – but talks have stalled and Real boss Jose Mourinho faces losing him. It has opened the door to City, who have sounded out his agent .

Ronaldo scored twice in Real’s 3-0 win over Granada on Sunday but refused to celebrate either goal, and revealed his frustration after the match.

He said: “I’m sad. When I don’t celebrate goals, it’s because I’m not happy.

“It’s a professional thing. Real Madrid know why I’m not happy.”

Ronaldo – who scored 46 league goals last season – is in Portugal preparing for their World Cup qualifier in Luxembourg on Friday.

Sources close to the player said: “This is a situation that has been brewing for a long time.”

City last night denied they are ready to move for Ronaldo, suggesting his agent Jorge Mendes is using the speculation to get his client a new deal in Madrid. But sources in Spain and Portugal insist their interest is real.